Typewriting machine



Nov. 17, 1942; w. A. DOBSON TYPEWRITING MACHINE Fild Sept. 16, 1959INVENTOR 'W/LL/A/V A. 00650 WW I ATI'ORNEY Patented Nov. 17, 1942TYPEWRITDIG MACHINE William A. Dobson, Wethersfield, Conn., assignor toUnderwood Elliott Fisher Company, New York, N. Y., a corporationofDelaware Application September 16, 1939, Serial No. 295,235

1 Claim.

This invention relates to ribbon-iced mechanisms for typewritingmachines, and more particularly to mechanisms of this character whereinthe reversing of the ribbon feed is automatically efiected in the finaltravel of the ribbon.

The invention has among its objects the provision of an automaticreversing ribbon feed mechanism having a minimum number of lightweightparts in a compact and reliably operative organization particularlyadapted for typewriting machines of the portable class.

Other objects of th invention are to provide a ribbon feed and reversingmechanism wherein the ribbon reversing control is adapted either formanual or automatic operation, and to provide an automatic ribbonreversing mechanism of substantially simplified structure andarrangement.

In its more specific aspect the invention provides a ribbon feedmechanism including slidably reciprocatory drive pawls cooperating withratchet wheels of each of the ribbon spools; these driving pawls beingconnected to, and reciprocated concomitantly by, the rocking movement ofa universal bail actuatable by any of the type actions of thetypewriter- The pawl and ratchet mechanism of each ribbon spool may becontrolled by a shiftable control member engageable with the drivingpawl and which also carries a holding pawl and a driving pawl spring,these elements being so associated that upon shifting the controlmembers concomitantly, the two pawls of one spool mechanism aredisabled, while the pawls of the other spool mechanism are operativelyset. The direction of shifting the control members correspondssubstantially to the direction of ribbon travel so that these membersmay be directly connected for concomitant shifting by a link which maybe so disposed relative to the path of ribbon travel as to be adaptedfor automatic ribbon reversing by having the link engageable byprojections on the ribbon adjacent its ends.

Other objects and anvantages will hereinafter appear.

Certain features of the reversible ribbon-feed mechanism hereindescribed form the subject matter of my copending application Serial No.295,296, filed September 16, 1939, now Patent No. 2,282,994, issued May12, 1942.

In the drawing,

Figur 1 is a perspective view of the preferred embodiment of theinvention, including only the related portions of the typewritermechanism, and

Figure 2 is a top plan view of same, omitting the type action" and theactuating universal bail.

In the embodimentof the'invention illustrated, a central type actionof'the'system similar to that of an Underwood portable typewriter isshown, to illustrate by way of example the preferred manner of actuatingthe ribbon feed mechanism. Each type action includes a key lever 4fulcrumed at 5 and having a'driving connection 6 to a sublever 1.Each'sub-lever is pivoted at 8 and is operatively connected by a link 9to a type bar ill fulcrumed at H on a mounting segment l2. Eachsub-lever 1 of the type action system includes a part such as a fingerl3 engageable with a universal bar [5 extending across the typewriterand supported adjacent each end by arms fixed to a rock shaft I6 pivotedat "on the main frame of the typewriter.

The bar l4 and the arms 15 constitute a bail oscillatable universally"by any of the type actions. Articulated to each of the arms It: at I8 isa slide arm I9 having a guide slot at its opposite end riding upon a'stud 2l mounted on the main frame. Each of the arms l9 extends in a foreand aft direction of the typewriter and includes an integral upstandingpawl arm 22 formed at its upper end to provide a driving pawl 23. Aspring 2 1 restores'the universal bail l4, IE to normalcy and thusreturns the driving pawls 23 to initial position after the drivingstroke.

The usual inking ribbon'25 traverses the printing zone of the platenthrough a ribbon guide 26 to and from suitable ribbon spools 2?removably carried on spindles 28 in the well-known manner.

Each ribbon spool spindle'has a ratchet wheel 30 arranged to rotatetherewith and disposed to co; operate with the corresponding drivingpawl 23 to effect travel on the ribbon. Each side wall of the typewritermain frame may include an inturned portion 31 providing a plate uponwhich each ribbon spool spindle 28 may be rotatably mounted. Shiftablymounted on each of the plates 3| adjacent each driving pawl 23 is acontrol member 32 preferably pivoted at 33 on the plate 3! and having anedge thereof extending alongside the driving pawl 23 for engagementtherewith. At the free end of each control member 32 an upstanding lug34 is formed to provide a mount for a bifurcated member 35 adjustablysecured to the lug by a screw 35. Ihe member 35 provides, in an integralstructure, a leaf spring 3'! and a holding dog 38 each formed of thetines of the member. In the operative setting of the control member 32,as shown at the left-hand ribbon spool, the holding dog 38 engages theteeth of its ratchet wheel 30 to prevent reverse rotation of same duringthe return stroke of the driving pawl 23. The leaf spring 31 of thebifurcated member 35 presses against the pawl 23 to yieldably hold sameengaged with its ratchet wheel 30. Each control member 32 has a fingerpiece 48 extending laterally therefrom to project through the adjacentside of the type writer mask for access by the operator to manuallyreverse the direction of the ribbon feed, and the control members 32 areconnected together by a link 4| extending across the machine forconcomitant shifting of the members 32.

At least one of the control members 32 is yieldably held in eiiectiveand inoperative positions by a detent shown best at the right of Figure2, which detent preferably comprises an arm 43 pivotally mounted at 44on the plate 3! and urged by a spring 55 to press against an edge of thelug 34. The arm 43 carries a mound 36 having oppositely inclined edgescoactive with the lug 34 so that in the condition of the parts as shownin Figure 2 the right-hand control member 32 is detented at itsinoperative position, and when the lug 34 is pressed to the oppositeside of the mound 46, the control member is detented at its efiectiveposition. It will be seen that when the furthermost projecting fingerpiece 43 is manually pressed, the direction .of ribbon travel isreversed in that both control members are conjointly swung so that theone feed mechanism is rendered operative while the other feed mechanismis disabled.

In the operative condition of either feed mechanism, the driving pawl 23under influence of its spring 31 engages its ratchet wheel 38 and theholding dog 38 is also engaged therewith, so that as the pawl arm [9 isreciprocated incident to the depression of a key lever, the spool 21 isrotated to wind the ribbon 25 thereon. As the control member 32 is swungto the inoperative setting, the holding dog 38 is moved to a positionfree of its ratchet wheel 39, and the driving pawl 23, being disposedbetween its spring 31 and an edge of the control member 32, is alsomoved to inoperative position free of the ratchet wheel. It will beobserved that the pawl-carrying end of each arm 22 assumes a motionlaterally of the typewriter in moving between effective and inoperativepositions, this motion being accommodated at the stud 2| which is ofsuch length as to permit the slot 20 to slide axially thereon.

In that the control members 32 are shiftable laterally of the machine toefiect reverse travel of the ribbon, that is, in the general directionof ribbon travel, the arrangement is particularly suited for anautomatically efiected ribbon reversal. The link 4| is provided with twointegral projecting members 4'! adjacent each of the ribbon spools 27,forming loops 48 disposed in the path of travel of the ribbon andthrough which the ribbon passes in traversing the printing zone.Adjacent each end of the ribbon 25, a projection such as a rivet 49 isafiixed thereto so that as the ribbon is unreeled from one of the spoolsthe projection 49 abuts the loop 48 and the further travel of the ribbonpulls the link laterally so as to concomitantly swing both the controlmembers 32 and thus reverse the positions of the driving pawl 23 and theholding dog 33 of each feed mechanism.

It will be seen from the foregoing that the invention provides anautomatic reversing ribbon feed mechanism having a minimum number of Ilightweight parts in a compact and reliably operative organization. Eachof the elements in the right and left feed mechanisms may be identicalin form, it being required only to make the correspondng parts in pairsof opposite hand. The link connecting each mechanism is also adapted foreconomic manufacture, in that same may be readily formed of a stripmaterial such as wire having the ribbon-engaging loops in tegrallyformed thereon. The arrangement of the parts is such that the machinemay be equipped for either or both the automatic and the manual ribbonreversing, in that the control members, being shiftable laterally in thegeneral direction of ribbon travel, are adapted for concomitantactuation by the connecting link and, being arranged in proximity to theside walls of the machine, may include the required finger pieces forthe manual reversing.

Although in this application there is specifically described oneembodiment which the invention may assume in practice, it will beunderstood that same is shown for the purposes of illustration, and thatthe invention may be modified and embodied in various other formswithout departing from its spirit or the scope of the appended claim.

What is claimed is:

In a ribbon feed mechanism for a typewriter; means operable to reversethe direction of ribbon feed, comprising a one-piece wire link havingbent-off pivot members at each end supporting the link for endwiseshifting and presenting integral upstanding loop portions intermediateits ends through which a ribbon may pass and adapted for engagement byribbon-carried means, to actuate th reversing means, the pivot membersholding said link non-rotative to maintain the loop portions inupstanding position.

WILLIAM A. DOBSON.

